PERFORMANCE OF FLOOD CONTROL WORKS AROUND DHAKA CITY DURING MAJOR FLOODS IN BANGLADESH (original) (raw)

The Disastrous Flood of 1998 and Long Term Mitigation Strategies for Dhaka City

Natural Hazards, 2003

The disastrous flood of 1998 was a result of excessiverainfall all over the catchment areas of the major rivers of Bangladesh. Dhaka City, which is surroundedby rivers on all sides, was seriously affected despite the completion of Phase I of the Dhaka IntegratedFlood Protection Project (DIFPP). Water entered into the protected part of the city throughhydraulic leakage such as buried sewerage pipes, breached and incomplete floodwalls, ungated culverts andinoperative regulators. The drainage network and retention ponds of the city were found to be in poorconditions and capacities of the pumping stations were found inadequate. There was a serious lack of coordinationbetween the agencies responsible for flood protection and drainage of the city. These issues must beaddressed to achieve long-term flood mitigation. In addition, feedback from both the experts andgeneral public indicated that completion of Phase II of DIFPP was essential to bring the eastern part ofthe city under flood protection. Other structural measures suggested in this paper include installing andmaintaining adequate drainage and pumping capacity and timely operation of regulators. This studyalso suggests a set of non-structural measures for flood mitigation that include protectingthe retention ponds, raising public awareness on maintaining the city drains, introducing landzoning and flood proofing in the eastern part of Dhaka, and stream lining institutional bottlenecks.

PLANNING FOR DISASTER MITIGATION IN FLOOD PRONE CITY OF DHAKA

Dhaka, the largest and capital city of Bangladesh, is a rapidly growing Mega city. Major environmental concern of Dhaka city is recurring natural disasters. Flood is actually the main natural catastrophic event now days for Dhaka city. To mitigate the flood hazard there is a Flood Action Plan for Dhaka, which was made after 1988 flood. Moreover, there are pre and post mitigation measures taken by Govt. Despite of these measures, Dhaka faces flood hazard in every year and the hazard is becoming more vulnerable day by day. So, there is a need for planning measures to mitigate flood hazard. In this thesis an attempt has been made to arrive at strategies for mitigating floods in the Dhaka city. The goal of the thesis has been achieved under five objectives. The phenomenon and characteristics of flooding in the city of Dhaka has been studied under first objective. The critical flood prone areas, causative factors, existing infrastructure problem that makes worst situation during flood and rainy season have been studied under second and third objective. Under forth objective review of Flood Action Plan of Dhaka has been studied. Suggestion for planning measures to mitigate floods has been studied under objective five. The analysis of the secondary survey data indicates that Dhaka faces two types of flood -monsoon flood and urban flood. This type of floods causes because of local heavy rainfall and blockage of natural drainage of water due to unplanned population settlement. Dhaka has both open and closed drainage system. Most of them are blocked due to solid waste dumping. As population is increasing day by day, slums have been taken place in the retention areas and along the canals & lakes. So, slum population is dumping solid waste as well as sewerage in the canals. It causes environmental hazard and blockage of natural drainage system. Moreover, natural drainage system is getting blocked by the nature (water hyacinth) also. So, storm water cannot be drained out properly during rainy season and it causes urban flood. These are major issues arrived from the analysis. At the end of the thesis some planning measures to mitigate the flood has been recommended. This recommendation has been divided into three categories. In the first category, the proposals of FAP should come true. Zoning of the area has been done also. In second stage the alternative allocation of urbanization has been worked out. The third step covers the preservation of wetlands, rejuvenation of canals, increasing the drainage capacity, increasing the public awareness and improving the situation by leg al instrument. An action plan has been prepared for a flood prone area called Kamrangirchar. Zoning has been done for the area. The zoning covers in three steps. Some other recommendations also have taken for the study area like- conservation of water body, protection of natural drainage system etc.

Effects of Flood Mitigation Measure: Lessons from Dhaka Flood Protection Project, Bangladesh

1996

Although, Bangladesh is subjected to perpetual floods every year, she suffered two of the most serious and devastating floods on record in 1987 and 1988 which lasted from later part of August to first part of September. Vast areas of the country including the Capital City of Dhaka with a population of about 4.8 million were flooded to an unprecedented degree with flood levels 1.5 m higher than normal for periods up to four weeks. In Dhaka City, it is estimated that about 200 sq km (77 per cent of the total area of 260 sq km) was submerged to depths ranging from 0.3 m to over 4.5 m (FAP 8B, 1991). About 2.4 million people (50 per cent of the city population) were directly affected by these floods. Conservative estimates of the floods suggest that loss due to annual flood is about TkI 250 milhon, and the damages to a 10-year (return period) flood and a 40-year (return period) flood are Tk 530 million and Tk 750 million, respectively (Bangladesh Water Development Board, Undated). Follo...

Non-structural flood mitigation measures for Dhaka City

Urban Water, 1999

After the disastrous¯ood of 1988, Dhaka Integrated Flood Protection Project (DIFPP) was undertaken as a part of the national Flood Action Plan (FAP). However, DIFPP focused primarily on the structural measures for¯ood damage mitigation. When the city was hit by another major¯ood in 1998, it became evident that non-structural measures contributed signi®cantly to¯ood damage reduction. This paper explores existing and proposed non-structural measures as a part of the long-term¯ood mitigation strategies for Dhaka City. The options examined in this paper include¯ood forecasting and warning, preservation of retention ponds, land use planning,¯ood zoning, emergency services, shelters,¯ood proo®ng,¯ood ®ghting and post-¯ood rehabilitation measures. Moreover, experiences from 1998¯ood indicate that coordination between agencies responsible for¯ood protection and drainage of the city can signi®cantly reduce the¯ood damage.

Flood Risk Measuring under the Flood Protection Embankment Construction in Dhaka Metropolitan Zone

The flooding is a common feature for problem solution in rapidly urbanizing Dhaka city. In this research, evaluation of flood risk of Dhaka city in Bangladesh has been developed by using an integrated approach of GIS, remote sensing with socioeconomic data. The purpose of the study is to evaluate the flooding risk concerning with the flood protection embankment in remarkable flooding events (1988, 1998 and 2004) and urbanization of Dhaka metropolitan zone. In this research, we considered the Dhaka city into two parts east Dhaka where is outside the flood protection embankment and west Dhaka where is inside the flood protection embankment. Using statistical data we explored the socioeconomic status of the study area population by comparing density of population, land price and income level. We have drawn the cross section profile of the flood protection embankment into three different points for realizing the flooding risk in the study area, especially in the historical flooding year (1988, 1998 and 2004). According to the physical condition of the study area, the land use/land cover map has been classified into five classes. Comparing with each land cover unit, historical weather station data and the socioeconomic data the flooding risk has been evaluated. Although various adaptation strategies for prevention infrastructure was developed on basis of 1988 memorial flood. As a result, urban area expansion has driven by infrastructure development by 10% and population growth by 5% inside the embankment area. The socioeconomic development such as; the average total income inside of embankment has been increased 10 USD while the income outside the embankment remain same.

Urban Flooding of Greater Dhaka in a Changing Climate: Building Local Resilience to Disaster Risk

2015

photos 3.1 Site investigation to measure sediment depth in box-culvert 3.2 Drainage pumps at Dholaikhal Pump Station, Old Dhaka 3.3 Pumping floodwater out of Hathir Jheel using temporary pumps, Central Dhaka 3.4 Kallyanpur Retention Pond in the dry season 3.5 Outlet of temporary drainage pumps on the Western Embankment near Rayerbazar, Kallyanpur system 3.6 Water inlet after garbage filtering at Goranchatbari Pump Station 61 3.7 Tin-shed house built on stilts in low-lying area of Khilgaon, Eastern Dhaka 3.8 Intake pipes of drainage pumps at Shimrail Pump Station, DND system 3.9 Drainage outfalls to Lakhya River in Narayanganj township at end of RK Mitra Road, eastern area and end of BK Road, southeastern area 6.1 Original Rampura sluice gates and new bypass channel used when gates are closed (Central Dhaka system) 6.2 Construction of new pump station at Hatir Jheel, Rampura (Central Dhaka system) 6.3 Laying new stormwater pipe in Gulshan area of Central Dhaka system 6.4 Resectioning and lining work at Katashur Khal near Mohammadpur (Kallyanpur system) 6.5 Temporary pumps located along the Western Embankment, Kallyanpur 8.1 DWASA sign next to Segunbagicha Khal warning against encroachment, connecting wastewater line to the khal, and garbage dumping 8.2 Motorized solid-waste collector belt at Hatir Jheel outlet of Panthapath Box-Culvert near Sonargaon Hotel (Central Dhaka system) 8.3 Hazaribagh Khal outlet (looking toward river) on the Western Flood Embankment near Rayerbazar 8.4 Low-lying area of Kallyanpur, showing floodwater mixed with wastewater 8.5 Discharge from Kallyanpur Retention Pond into Turag River 8.6 Segunbagicha Khal, Central Dhaka system tables 2.1 Relationship between Population Density and Land Levels 2.2 Model Simulations for the Detailed Study Area xii Contents Urban Flooding of Greater Dhaka in a Changing Climate •

Flood Control Projects in Bangladesh: Reasons for Failure and Recommendations for Improvement

Disasters, 1995

Flood control and drainage projects in Bangladesh are intended to give protection from main river floods, flash floods in the east and northeast of the county, and saline intrusion in the lower delta and to improve drainage in order to avoid crop damage. While in some cases such projects have had positive results, in many others their benefits have fallen well below expectations. One of the major reasons for the poor performance of projects is embankment failure, brought about by poor planning, design, construction, operation and maintenance. Recommended measures to improve the efficiency of projects include the involvement of local people in the planning and operation of projects, better training of management staff and the allocation of adequate funds for maintenance.

An Analytical Study of Flood Management in Bangladesh

Bangladesh along with the state of West Bengal in India is situated in the lowest area of the Hindu Kush -Himalayan Region (HKH) and is famous as one of the highest flood prone countries in the world. Flood to some extent is an annual expected and well-come event for many reasons for this country. But extreme flood inundates more than half of the country's landmass causing immense suffering to the human life, damages properties and economy. Aim of the flood management in Bangladesh is to minimize damages or to avoid disastrous situation. Though the country is in the eastern part of the lowest ridge of HKH but geography and location of the country make hydrology of Bangladesh very diverse, complex and unique. The North-Eastern part of the country has the river networks with upper hilly catchments having one of the world's highest rainfall intensity and causes frequent flash floods. In the North-Western part rainfall intensity is lower, higher altitude and mighty perennial river network causes river flood. The South-Eastern part has moderate rainfall intensity, hilly as well as coastal plain land, flashy and tidal river network causes both the storm surge and flash flood. The South Western region has also moderate rainfall, coastal plain land and tidal rivers cause storm surge due to cyclone. Principles of flood management in the country based on these different types of floods and geographical conditions either by non-structural or structural measures. As a non-structural measure for flood loss minimization, flood forecasting and warning services has been emphasized. Structural measures began in late 60's by implementing number of flood control projects.